Describing somebody as a show-off carries an implicit endorsement of their capability: someone can only "show off" if they actually have something to show. An individual who seeks attention that they are not perceived to deserve is usually described much more dismissively as an attention-seeker or loudmouth

Jane: I bought a new car, i have money and i can have everything i want.
Lu: /showoff

1. Someone that flaunts their money by paying people to do stupid things, such as eating an aluminum foil cheetos bag for $100
2. Specifically in high school, a student that offers exorbitant amounts of money for other kids to do his/her homework, when a smaller amount would work
3. Someone who routinely takes friends out to steakhouses for lunch or dinner and proceeds to pay for everyone.
4. Someone who makes fun of others solely because they are not as wealthy
5. Someone whose main insult line is "i can buy and sell 100 of you"

Great Neck South used to have an infmaous show off, but his days of bribing, flaunting, and scheming are over

A wannabe loser who is so desperate to fit in and is soo ugly, that you go total Texas Chainsaw Massacre on. He does things that make him look "cool" (when he really looks like an asshole) to impress everybody and show of his "talents" (which he doesn't have). Gets made fun of A LOT, mostly by nerds, losers, sensitive wusses and science geeks. See Anthony Brito